Bayou Sauvage Ridge - Geology In The Wetands
No rocks, no geology-right? Actually, once you know what to look for, it's
easy to see evidence of geology at work in this wetland environment.<br>
The geologic features of the Mississippi River Delta region are of relatively
recent origin. As the dynamic Mississippi River overflowed its banks in
spring floods, bayous carried water and sediment into adjacent marshes
or to the Gulf.<br>
Silt carried by these bayous accumulated in the form of natural levees, or
"ridges," along the bayous' banks. These ridges formed important high
ground for settlement and transportation as humans populated the delta
region. Native villages and the "Old Spanish Trail" (later U.S. 90), the first
roadway into New Orleans from the east, were situated on the ridges in
this area.<br>
The result of the delta's pattern of flooding and sediment deposits is a
landscape that may seem "upside down" compared to other regions. The
highest lands in the delta are natural levees next to the rivers and bayous.<br>
As you move away from delta waterways, a very gradual downward slope
typically leads through habitats such as cypress-tupelo swamps and
prairies into open marsh. This elevation change may be only a matter of
inches, but the effects on plants and animals can be dramatic.